You also added an element I think many are overlooking as a sound source. A source that can effectively transmit vibration throughout a house worse than usual too; you are connecting to a wall.
If it is on legs near the wall, you could sandwich foam or sound board bewtween layout & wall, & go to nylon screws with rubber backing to the wall since legs are supporting it up structurally you only need to keep it from shifting as you lean. There are also rubber expansion insert nuts ("well inserts") with metal threads that are excellent for isolation especially if used with a nylon machine screw,(and hold very well)
Brick is no biggie, plaster somewhat better, but drywall can turn into a big percussion instrument if not isolated. Ask someone with a shelf layout 
Felt, cork, rubber, homasote, caulk, carpet, etc under just your track helps with direct noise and transmitted noise & the "echo" off the bottom.
The surface covering helps absorb sounds reflecting up.
